A cell free system for the synthesis of cellular and viral mRNA will be developed. This will require the isolation of enzymes capable of performing various aspects of mRNA production known to occur in vivo. Ras substrates for these enzymes viral RNAs known to be precursors to mRNAs will be used to determine whether they can be converted to recognizable processed molecules as found in infected cells. BIBLIOGRAPHIC REFERENCES: Weber, J., W. Jelinek and J.E. Darnell, 1977, The Definition of a large viral transcription unit late in Ad-2 infection of HeLa cells: Mapping of nascent RNA molecules labeled in isolated nuclei, cell 10, in the April issue. Rhodes D.P., G. Abraham, R.J. Colonno, W. Jelinek and A.K. Banerjee, 1977, Characterization of Vesicular Stomatitis Virus, RNA species synthesized in vitro, J. Virol. 21:1105.